1. Field of the Invention
The present invention relates to a tape cassette for digital recording/reproducing, such as DDS (digital data storage) and DAT (digital audio tape), and to a combination structure of the tape cassette and a driving device for driving the tape cassette.
2. Related Background Art
The conventional DAT or DDS tape cassette for digital recording/reproducing, in a case body consisting of an upper case and a lower case thereof, supports a couple of hubs around which a tape is wound so as to be rotatable, and includes a couple of holes in the lower case into which the driving spindles of the recording/reproducing device are inserted, and a slider which covers the couple of the holes slidably. The couple of hubs around which a tape is wound is arranged between the upper sheet and the lower sheet. For stabilization of tape running in the tape cassette, for instance, in a gazette of Japanese Patent Application Laid-Open No. 9-73758, it is laid open to provide projections and recesses on the friction sheets pinching a couple of the hubs to be rotated, around which a tape is wound.
In a gazette of Japanese Utility Model Application Laid-Open No. 7-41775, it is also laid open to provide a spring member which pushes the hubs pinched between the friction sheets, to the lower case.
Although DAT or DDS tape cassette for digital recording/reproducing is used for music and data storage of a computer, recently, it is in need of bigger capacity of memory for data storage. On the cassette tape for such a usage, when the driving spindles of the driving device is engaged with the hubs or during tape running, even if the locations of the hubs are slightly slid vertically, it will be a problem to make an instability of tape running. If such problem arises, there may be a possibility of an error.
Against such problem, even if projections and recesses are provided on the friction sheet as laid open in the gazette of Japanese Patent Application Laid-Open No. 9-73758, since such the projections and recesses are provided in order to prevent from disarrangement of tape winding, not to set the hubs to a regular position, a sufficient effect may not be obtained. Although it is possible to utilize a spring member as laid open in the gazette of Japanese Utility Model Application Laid-Open No. 7-41775, since a quantity of parts may be increased, and assembling processes may consequently be increased, it will make a cost up. In addition, it needs a space for arrangement of the spring members, and therefore makes a difficulty to keep the space in the tape cassette.
It is an object of the present invention to provide a tape cassette capable of preventing an error from occurring during recording or reproducing, by positioning the hubs to the regular position during tape running thereby stabilizing of the tape running, and a combination structure of the tape cassette and a driving device for driving the tape cassette.
According to the aspect of the invention, the tape cassette is provided with a case body, and a couple of hub members stored rotatably in the case body, around which a tape-like member is wound, wherein the hub members includes through holes for insertion of a rotative driving spindles of the driving device through an insertion openings and a plurality of spline projections formed at an interior of the through holes, and the spline projections widen toward the insertion opening gradually.
According to the tape cassette, since the spline projections in the through hole of the hub member is slanted so as to widen toward the insertion opening, when the rotative driving spindles of the driving device engage the spline projections widened toward the insertion opening, and the hub members are rotatably driven, the force toward the insertion opening is exerted on the hub members, so that the hub members are moved toward the insertion opening and the hub members are rotatably driven stably at the moved position. Thus, the tape running at the hub members is stabilized, an error is prevented from occurring during recording and reproducing, accordingly. Further, a sheet part may be arranged between the case body and the hub pats.
During rotative driving of the hub members with the driving device, a side face of the engagement projection of the rotative driving spindles contacts with a side face of each the spline projection, and the hub members are moved toward the insertion opening and rotated thereat.
According to another aspect of the invention, a combination structure of the tape cassette and the driving device is, of a combination structure of the case body, the tape cassette including a couple of hub members stored rotatably in the case, around which a tape-like member is wound, and the driving device including the rotative driving spindles for rotative driving of the hub members when the tape cassette is set therein, the combination structure includes the hub member including a through hole for insertion of the rotative driving spindle through the insertion opening and a plurality of spline projections formed at an interior of the through hole, the spline projections widening toward the insertion opening gradually, and engagement projections for engaging with the spline projections and arranged at the rotative driving spindle.
According to the combination structure, when the engagement projections of the rotative driving spindle of driving device engage the spline projections slanted so as to widen toward the insertion opening of the through hole, the force toward the insertion opening is exerted on the hub members, the hub members are therefore moved toward the insertion opening, and the hub member is rotatably driven stably at the moved position. Thus, the hub member is not moved in any direction in which the through hole extends, during driving in the driving device, the tape running is therefore stabilized, and an error is prevented from occurring during recording and reproducing accordingly.
By provision of the engagement projection of the rotative diving spindle so as to match the form of spline projection, the hub member is forced toward the insertion opening more strictly, and the tape running with the hub members is therefore stabilized more steadily. During rotative driving of the hub members with the driving device, a side face of each the engagement projection of the rotative driving spindle contacts with a side face of each the spline projection, and the hub member is moved toward the insertion opening and rotated thereat.
Each the spline projection includes a tapered portion at the insertion opening end, and each the engagement projection of the rotative driving spindle has a wide portion in correspondence with the tapered portion, and during rotative driving of the hub members by the driving device, each the wide portion contacts with the tapered portion to control the moved position of the hub member. In such a manner, the position of the hub members, which are moving during the rotative driving, may be regulated and adjusted.